I've been searching about Sword Art Online season 2 ! and there are some rumors that there will be a second season the name of it would be different then the origanel name 'Sword Art Online' the new name of the season 2 will be 'Gun Gale Online'There are already some release dates but they aren't sure of them ^^

There is a manga of Sword Art Online that haves the part of Gungale Online, but I don't know if it will be anime :SIn the manga appears a character called "Yuki Konno", I think that she's the sister of Asuna :3[link]